Electrical equipment is designed to operate at certain voltage and currents. The electrical equipment may be capable of handling certain spikes in voltage and/or current. The electrical equipment may include spike protection circuitry to protect against certain types of spikes (e.g., reduce, limit, remove, and/or isolate the spikes so the spikes don't reach the electronics therewithin). Furthermore external surge protection devices may be utilized to further protect the electrical devices.
The spike protection circuitry is limited in the type of protection it provides. Lightning storms may create surges that may cause damage to the electrical equipment. In areas where lightning storms are common this may produce a wide variety of surges/spikes.
FIG. 1 illustrates an example connection of a local area network (LAN) 100 within a subscriber location 110 to a wide area network (WAN) 120 via an interface device 130. The WAN 120 may be any of a various of networks including, but not limited to, a telephone network, a cable network, a digital subscriber line (DSL) network, or a satellite network. The interface device 130 may extract data from communication lines of the WAN 120 and route it to appropriate devices on the LAN 100 and may receive data from the devices on the LAN 100 and transmit them to the WAN 120 over the communications lines.
The interface device may be designed to account for spikes and certain well defined surges. However, it is possible that the interface device may encounter a variety of surges having unknown magnitude in voltage, current and energy. This may be especially true in areas that are susceptible to lightning storms and/or other WAN's that are not equipped to handle prevent/limit these surges/spikes (e.g., are not well grounded). Without proper surge protection for the interface devices they may be damaged and/or destroyed by these surges.